Nasogastric (NG) tube insertion is a routine medical procedure involving the placement of a thin, flexible tube through the nasal cavity, down the esophagus, and into the stomach. This intervention allows healthcare professionals to provide short-term nutritional support and medication to patients who cannot safely swallow or eat orally. The NG tube is also frequently used for gastric decompression, which involves connecting the tube to suction to remove stomach contents and secretions, relieving pressure from conditions like bowel obstruction. Given the tube’s proximity to the airway, accidental placement into the lungs is a risk, making proper technique and verification paramount for patient safety.
Pre-Procedure Preparation and Assessment
Before attempting insertion, the nurse must gather all necessary supplies and complete a thorough patient assessment to maximize success and minimize risk. Required equipment typically includes the NG tube, water-soluble lubricant, a syringe for aspiration, pH indicator strips, a securement device, protective personal equipment, and water for the patient, if permitted. The appropriate tube size, typically between 8 and 12 French for adults, must be selected.
A proper assessment involves reviewing the patient’s medical history for contraindications. Absolute contraindications include severe maxillofacial trauma, recent nasal or esophageal surgery, and a suspected basal skull fracture, as these increase the risk of intracranial placement or perforation. Relative contraindications, requiring careful consideration, encompass conditions like uncorrected coagulation disorders, esophageal varices, or recent caustic ingestion due to the heightened risk of bleeding and trauma.
The next step is to accurately estimate the length of the tube needed using the Nose-Ear Lobe-Xiphoid process (NEX) measurement. This technique involves holding the tube tip at the patient’s nostril, extending it to the earlobe, and then continuing down to the xiphoid process (the lower tip of the sternum). Although the NEX method is standard, it is an estimate. The determined length is then marked on the tube to serve as the target insertion depth.
Step-by-Step Insertion Technique
The physical insertion begins by positioning the patient in a high Fowler’s position, sitting upright with the head of the bed elevated to at least 45 to 90 degrees. This position helps prevent aspiration and utilizes gravity to aid tube advancement. The nurse should assess the patient’s nostrils for patency by asking them to occlude one side and breathe through the other, selecting the clearer nostril for insertion. Once the nostril is chosen, the first 3 to 4 inches of the tube tip should be lubricated with a water-soluble jelly to reduce friction and mucosal trauma.
The tube is then gently inserted into the selected nostril, following the natural curvature of the nasal passage by aiming backward and downward along the floor of the nasal cavity. As the tube reaches the nasopharynx, which is often met with slight resistance, the nurse should instruct the patient to tuck their chin toward their chest. This chin-to-chest position helps close the trachea and open the esophagus, directing the tube toward the stomach.
The patient, if conscious and able, should be encouraged to swallow or sip water through a straw as the tube is advanced to the pre-measured mark. Swallowing helps propel the tube down the esophagus and minimizes the risk of coiling or entering the trachea.
If the patient experiences severe coughing, choking, or signs of respiratory distress, the nurse must immediately stop advancing the tube and withdraw it slightly until the distress subsides, checking the back of the throat for any coiling. The procedure should be halted and the medical team notified if significant resistance is met or if repeated attempts are unsuccessful.
Confirmation of Placement
Confirmation of NG tube placement is the single most important safety step, as misplacement into the tracheobronchial tree can lead to fatal complications like aspiration pneumonia. For initial placement, X-ray visualization is considered the gold standard verification method. A chest X-ray provides an indisputable image of the tube’s tip location in relation to the diaphragm and stomach.
The primary bedside method for verifying placement is testing the pH of aspirated gastric fluid, which must be performed before administering any feed or medication. The nurse aspirates a small amount of fluid from the tube using a syringe and tests a drop on specialized pH indicator paper. A tube correctly placed in the stomach will typically yield an aspirate with a highly acidic pH level of 5.5 or below.
If the tube is misplaced in the respiratory tract, the aspirate will usually have a much higher, more alkaline pH, often above 6.0. If a bedside pH check is inconclusive or aspiration is unsuccessful, an X-ray must be obtained to confirm safe placement. Nurses must avoid the unreliable practice of auscultation, often called the “whoosh test.”
Managing Difficulties and Post-Insertion Care
A common difficulty during insertion is the tube coiling in the pharynx, which often causes the patient to gag or cough excessively. If this occurs, the nurse should withdraw the tube until the coiling is no longer visible and then re-attempt advancement, coaching the patient to swallow more forcefully. If the tube meets resistance, gentle manipulation or switching to the alternate nostril may be necessary, but forcing the tube is strictly avoided. If three attempts at insertion are unsuccessful, the procedure should be stopped, and a more experienced clinician should be consulted.
Once correct placement is confirmed, post-insertion care begins with securing the tube to the patient’s nose using a proper securement device or hypoallergenic tape to prevent movement and accidental dislodgement. The nurse must note and document the centimeter mark on the tube where it exits the nostril. This mark serves as a baseline for checking for tube migration with every shift and before every use. Skin care around the insertion site is performed at least daily by cleaning the area and applying fresh tape to prevent skin breakdown.
Routine monitoring is required to ensure the tube remains patent and correctly positioned. The tube should be flushed with water (30 to 60 mL) before and after intermittent feeds, medication administration, and at least once per shift during continuous feeding to prevent clogging.
Documentation must include the date and time of insertion, the tube type and size, the verified location of the tip, the method of confirmation, and the patient’s tolerance of the procedure. If the patient develops signs of tube intolerance (e.g., abdominal cramping, nausea, or vomiting) or if the external measurement changes, the nurse must recheck the tube position and notify the provider.